Too much Sun?

What a day: the last of the second heatwave in the UK year (so far) with temperature records having been broken multiple times and the whole thing made far worse by elevated levels of humidity; and what did I choose to do? I chose to stand in the Sun from ten in the morning until gone three in the afternoon.

Crazy? Maybe – but I prefer to believe that it was because I had the welcome chance, with three friends from my local amateur astronomy society, SEKAS, to show people our life-giving local star in all its energetically chaotic glory. The event that gave us this opportunity was my local village fête which, despite the uncomfortable weather, attracted large numbers of individuals, couples and families. Some of these lovely people I knew already, others I was meeting for the first time – either way, there were so many of them interested in what we were doing that the four of us barely stopped talking throughout the day. (The exception to this were the necessary times when we tried to keep hydrated; I was glad of the many bottles of chilled water I’d packed into a ‘cool-bag’ … and my sunscreen and wide-brimmed hat.)

Back in April I had contacted the Village Hall Committee, who support the annual fête’s organisation. Via our local social media page, I floated the idea of offering a safe solar observing experience. I’d half expected that I’d be told that it wasn’t really the sort of thing for a community fair – but the organisers evidently have a wider vision 😊. As a lovely bonus, the person who replied to my email, Tricia, reminded me that she’d stopped to chat one night whilst walking her dog – I was in my front garden with a telescope, naturally – and that I’d offered some advice on buying a telescope. Apparently, she now owns one … excellent!

In the two months between the gift of a south-facing pitch and the fête actually happening I had offers of help and support from fellow members of the South East Kent Astronomy Society – phew! I also tried to prepare the ground a little by posting a few of my own solar images so that people might get an idea of what to expect: “Just to whet your appetites in advance of the Blean Village Fête – at which, clouds permitting, you'll be able to see this sort of thing for yourselves - here's a some images of the Sun taken a few days ago from my garden. We'll have special equipment with us to enable you to do this safely - please, please, please don't look at the Sun directly as you can easily cause damage to your eyes ... and never, ever through binoculars or a telescope as blindness will follow. The whole-disk image was taken using a filter which let's all colours of the rainbow through but reduces the total by 99.999% in order not to damage the camera. Notice the three active regions (aka sunspot groups). Next is a close-up view around one of the sunspots - but this time it's taken using a specialised filter which only permits through one particular wavelength (colour) of light which comes from energised hydrogen. This has the beauty of picking out the chaotic and very energetic surface magnetic field associated with sunspots - just look at those swirls! Do you notice that there are whiter patches to complement the cooler dark sunspots? These are called plages, and they are regions where the surface is hotter than average. The darker loops are prominences that we're effectively observing from overhead. Finally, by over-exposing the disk of the Sun I managed to capture a very impressive prominence: super-hot plasma thrown out into space along the Sun's magnetic field lines. This one is many, many times the size of the Earth.”

Arriving at 10 am, we spent the next hour setting up an array of telescopes and getting their associated bits and pieces powered up. There were three fully automated ‘roboscopes’ in use as part of this array and they attracted a lot of attention. Mostly, this went smoothly – apart from one of my accessories which simply wouldn’t play ball; there’s always one. (Photos by the SEKAS Chairman, Ben Harding, and by the person who has responsibility for the SEKAS observatory site, Ashley Fuggle.)

We tried to introduce the experience by using a simple Newtonian reflecting telescope with its image projected onto a white background. Not only does this serve to illustrate that the Sun’s native colour is off-white and not yellow, but it revealed the sunspots nicely. (I’ve written about the colours of the Sun before if you’d like more background information: here and here.) Also, by placing a piece of card at the focal point of the telescope and noticing that it starts burning very quickly one immediately sees why looking at the Sun without appropriate equipment is a seriously bad idea. Other telescopes revealed crisp images of our white Sun and the day’s active sunspot regions by filtering out the majority of its light before it even enters the telescope itself. These are called white-light filters because they allow through a tiny fraction of all the colours (wavelengths) of the rainbow.

This is a colour image of the Sun taken on the day (by Ashley Fuggle, cropped and augmented by me) using one of the three smart telescopes in use – these impressive ‘roboscopes’, which may be controlled from an app on a smartphone, have a built-in astronomical camera. Each active region (- in this case a sunspot or group of sunspots) is given a numerical designation; for example, the large group centre left is AR-4478. To give you a sense of scale, the blue dot to the left of that region represents the size of the Earth: one could fit 109 ‘earths’ across the diameter of the Sun’s disk.

A highlight of the day for many people was the chance to look at the Sun not in white light but through a filter which eliminated all the wavelengths (colours) of light other than one of the wavelengths emitted by hydrogen, which happens to be a pinkish red. The advantage of this special and highly non-trivial method is that one can observe the flame-like prominences shooting out from the edge of the Sun’s disk. Prominences, the shape of which is influenced by the Sun’s strong magnetic field, are made from the Sun’s matter; in the main, this material falls back into the Sun under the action of its gravitational attraction. Sometimes however, the material has enough energy to break free and to stream out into space as a solar flare – if one of these travels in our direction then, a couple of days later it’ll arrive at our atmosphere and generate the aurora (the Northern and Southern Lights). If it’s powerful enough, we can even see the Northern Lights in the south of England. (Images by Ben Harding, edited by me.)

All-in-all a lovely, if hot, day for those of us who’d volunteered to offer the experience – and judging by the comments made on the day and on the village’s social media page in the days after, the whole thing was a great success. We’d love to return next year if they’ll have us. In fairness, I ought to share the comment of one person who declared that they’d already seen too much of the Sun and didn’t want to see any more – oh well, it’s not possible to please all of the people all of the time 😉

Attenborough in space

Engaged, inquisitive, sharp-eyed and bright: ‘Attenborough Class’ at Langdon Primary School, about five km northeast of Dover, were a real joy to meet. Attenborough is a mixed Year 1 and 2 class, so the pupils are six/seven years old; this is definitely the youngest group of budding scientists I’ve had the pleasure of meeting. However, any nervousness on my part – and there was plenty! – was dispelled when the first group of pupils came out in the care of their teaching assistant, Clare. They were evidently keen to see something new, and having recently completed a space-themed study topic they also had a pretty good idea of what it was they’d be looking at.

What a delightful village primary school, with a mix of ‘traditional’ and modern buildings quietly set within grass and all-weather playing areas and with mature trees dotted around. My classroom for the morning was a patch of lawn in front of the Headteacher’s office window – the green arrow will point it out for you. (The headteacher, by the way, is my totally wonderful son, Andrew.) The view south from there was over the fence and across the small staff car park. Fortuitously, a large branch had recently been removed from the over-hanging tree so that we had a good view of the Sun’s path – and of the Sun itself as the clouds kindly thinned and cleared.

My first task with each small group was of course to make sure they knew never to look at the Sun without the sort of special equipment I was using. After that I introduced them to my pet robot and its view of the Sun … I had set up a Dwarf3 smart telescope to track the Sun so that I could show them an image on my ’phone. It was easy to point out from the image the string of three significant sunspots visible that day and to talk about what sunspots were. Having laid the foundations, each of them got the opportunity to view the Sun in more detail through the eyepiece of a telescope fitted with an appropriate solar filter. As is the case for first-time observers of all ages, it can be tricky for some to position their eye at the ‘sweet-spot’ near the eyepiece, but with a little coaching from Clare or from me everyone got to see the Sun as they’d not seen it before. Clare, and then class teacher Emma and other staff members also had a look; naturally, who wouldn’t want to have a go.

 

(Images supplied by the school in accordance with their rules on privacy and parental consent. The bald head is my responsibility.)  There’s nothing quite like having the privilege and the pleasure of watching someone see something qualitatively new to their experience, and to know that a seed of curiosity will have lodged in their minds. Germination, growth and fruition will depend on so many things in their young lives, but maybe …

My initial question to whoever was first in each group was the same: what colour is the Sun? It came as a surprise to everyone that it wasn’t the yellow they all used in their artwork: “It’s white!” was invariably the answer I got. Once everyone in the group had seen it we were able to talk briefly about the Sun’s colour and texture; the shell of a chicken’s egg was our working analogy. (For more detail on the nuanced topic of the Sun’s colour please see my earlier post on the subject, here.) In addition, several of the more observant pupils challenged my contention that three sunspots were visible – that’s all we could see from the raw Dwarf’s image – and declared that there were four. Brilliant: objective observation and the courage to defend it. I truly hope they continue in that vein; it bodes well for the future.

This is the view through my Dwarf3, post-processed when I got home to remove the annoying colouration added by the Dwarf’s solar filter and so that I could identify and label the active regions. (I have been meaning to replace their stock filter with something neutral, akin to the filter I made for the other telescope used that morning: a Skywatcher 72ed refractor fitted with a Baader solar film filter – see my earlier post, here, for details.)

As a parting gift I gave each of them a pair of eclipse-viewing glasses and told them about the partial eclipse that will be visible over the UK in August, during their school summer holidays. In fact, there will be two in August 2026 (see here):

• 2nd August; the partial eclipse will begin around 9am BST. It will reach maximum at 10am and end around 11am. At maximum roughly 45% of the Sun will be in shadow.
• 12th August; this partial eclipse will almost be total, with around 90% of the Sun being obscured by the Moon at the maximum. It'll begin at 6.17pm BST, with maximum at 7.13pm.

The glasses came with repeated warnings about not looking directly at the Sun without proper safety equipment. (These were the solar viewing glasses I managed to get at Astrofest earlier in the year, which I wrote about here.) Furthermore, I made the point that if the glasses were damaged in any way they shouldn’t be used. At this point one young person declared that he’d therefore definitely not be showing them to his brother 😉.

I’d love to go back after dark someday and help run – with friends from my local astronomy society – a stargazing evening; maybe next Winter when it gets dark early and there’s a clear sky, so that the pupils can bring their parents/carers with them. However, that’s in the hands of the school. In the meantime, of one thing I am certain: Sir David Attenborough would be proud of them.

Postscript:

A while after posting this I got a lovely thankyou card:

The House of Astronomy: Astrofest

It was my first time.

I’d toyed with the idea before, more than once. Attending a genuinely large-scale amateur astronomy event had been an appealing thought ever since I had reacquainted myself in retirement with the chief of my geeky teenage hobbies, but … The annual European Astrofest, held this year in Kensington Town Hall, London, was too good a chance to miss. Apart from anything else, we’ve had two years of the most miserably damp and cloudy Winters in my part of the world with telescopes tucked away unused – so, in the absence of ‘traditional’ cold, crisp and clear nights, maybe a conference on astronomy would cheer us up.

I travelled with three fellow members of the South East Kent Astronomy Society (SEKAS). It was a long day – beginning with an alarm at 05:00 so that I could catch an early train to London, meet my SEKAS friends and be at the venue in good time for the first of several talks. SEKAS is one of three local amateur astronomy groups that I count myself a member of, but it holds two key advantages for me: it is dedicated to outreach and that resonates with my own longstanding passion for science communication, and it streams its monthly meetings online. The latter is really useful to those of us who choose not to drive on less familiar roads after dark. (It’s sad that the three SEKAS outreach events I participated in recently were all messed up by cloud and rain.) One of the very first happy discoveries of the day was that the SEKAS crowd have a tradition of buying a breakfast in a small, but perfectly formed, café off Kensington High Street. I’m glad I’d only had a very light pre-dawn breakfast, but this still made me feel a little like a hobbit enjoying Second Breakfast. I’m grateful to Andrew for supplying photographic evidence.

Astrofest ran for two days, but I booked in for the second day only. In future years I’d be tempted to do both days given the quality of the talks and the breadth of the trade/society exhibits spread over three floors. There were two talks on the Friday schedule for this year, for instance, that I’m particularly sad about missing: Prof. Michele Dougherty, the Astronomer Royal and a principal Investigator on missions to Saturn and Jupiter, and Sir Brian May who recently published a book of 3D galactic images. However, I enjoyed several excellent talks on the day I was there which covered a range of contemporary research as well as a wonderfully nostalgic look at what is still, after more than four decades, my favourite space exploration mission.

A quick snap on my phone before the lights went down and one of the talks got started – just to illustrate the fact that these sessions had audiences of several hundred amateurs like me.

First up was Dr Steph Yardley and her stunning images and video clips of the Sun derived from ESA/NASA’s Solar Orbiter data. In complete contrast, Josh Howgego talked about his own home-grown attempts to sift out from the detritus in his gutters a few examples of the enormous quantity of micrometeorites that reach the Earth’s surface each day. There’s no doubt that his science journalist’s take on the subject will motivate the clearing of a great many gutters in the next year or two. Moreover, it reminded me of a recent research project supervised by a space scientist at my own former university (Dr Penny Wozniakiewicz) which involved vacuuming the roof of Canterbury Cathedral. There were talks which reviewed ESA’s past, present and planned solar system missions; that looked at the use of polarised light as a means of mapping a galaxy’s magnetic fields; that considered the engineering challenges associated with making the very best telescope mirrors; which outlined the NASA Psyche mission en route to an asteroid primarily made of iron and nickel. However, the session that dug deep into my lifelong fascination with space exploration was the interview of Dr Garry Hunt by Prof. Lucie Green. Garry had been the only British Principal Investigator on the imaging team associated with the Voyager missions. Almost irrespective of what he actually said – which was interesting in its own right – it was such a pleasure to be able to revisit this pair of amazing ‘grand tour’ missions. It’s also salutary to remember that after decades flying at truly prodigious speeds the Voyager satellites are still less than one light-day away. (The nearest stars are, remember, several light-years away.) As Douglas Adams informed us in his radio play The Hitchhiker’s Guide to the Galaxy* “Space is big. You just won't believe how vastly, hugely, mind-bogglingly big it is”

A very low-quality image of Garry and Lucie on stage discussing the Voyager missions. In passing, the monitor screen to the right displayed speech-to-text in real time: it was surprisingly effective, even for one later speaker who had a heavy accent.

Much as I love learning, there was more to the day than that alone. For example, it gave me another opportunity to spend time with and to get to know better some of my fellow SEKAS members and astro-enthusiasts. Not only do they possess between them a seemingly inexhaustible fund of useful and constructive advice, but they’re also a pleasure to be around; it’s a nice combo. Beyond that I had the fun of putting faces to the names I’ve been coming across online for a while: the folk from First Light Optics for instance, from whom I’ve bought an embarrassing number of bits and pieces#, and individuals like Gary Palmer who got me started on imaging the Sun using narrow-band filters (see my earlier post here). Mary McIntyre, who is a frequent contributor to the BBC Sky at Night magazine, was running a workshop on lunar sketching; I wish I could, but it would be embarrassing. The national astronomy societies and several interest groups were there in force, some of which I’ve been supporting for years: the BAA for instance, and Dark Skies (see also here).

One DIY display caught my eye. It was the SKAO (- originally the Square Kilometre Array, SKA, back in the days when I first started hearing about it). Hardly a DIY project on the face of it, but they showed a demonstration of a basic radio telescope fabricated from an umbrella, a tin can and some simple circuitry connected to a laptop. With it, they claimed to be able to detect the arc of the Milky Way. I might have a go at this one day – at the very least it would give me something to do on a cloudy day.

And then there is the abundance of opportunities to spend money … I mean, serious money! I resisted, naturally 😉. However, that’s not to say I didn’t gaze with a modest level of avarice now and again. For instance, there was a display outlining the plan for an observatory hosting site in Oman away from serious light pollution and in a location boasting ten times as many clear nights per annum as I get. There are several such sites in existence around the world already of course – indeed, the telescope used for my introduction to solar imaging was sited in Spain and accessed via the internet – so the model is proven. It will be interesting to see whether this new proposal will come to fruition; I wish them well and I’d love to be able to take part, but I’m simply not in that league. In passing, the proposal is labelled Dar Al-Falak which translates as House of Astronomy, and which inspired the title of this post.

I ought to confess that I did spend some money before the end of the day. There was a stand with meteorites for sale and I simply couldn’t resist. I bought a small fragment of the Campo del Cielo iron meteorite (£8/€9) and a teeny, tiny fragment of lunar meteorite NWA11273 (a feldspatic breccia, £14/€16). Next stop, a rocky meteorite and maybe something from Mars? I also bought enough solar viewing glasses for a whole primary school class in preparation for my next school visit; one stall associated with a major astro supplier asked £69/€79 for 25 (!) but I found another stall, run by a lovely chatty couple, who gave me 40 for £30/€35 – yes please 😊

* The book spin-off (Pan Books Ltd, London, 1979) was based on the original BBC Radio 4 series of the same name which ran from 8th March 1978 to 12th April, with subsequent series to come later. I remember listening to this late-night innovative radio play with rapt attention, along with my wife and a couple of friends in a bedsit in Leicester. (One of those friends went on to become a professional astronomer, spending years working on the IRAS infra-red telescope – forerunner to both the Hubble and the James Webb space telescopes.)

# Other companies are available, like Altair Astro from whom I’ve bought all four of my CMOS astro-cameras and one of my telescopes (- I’ve mentioned them in previous posts), and so many more.